stub in hook to create database if not existing / do a migration

[cldellow]

...do we need a migration script? Can we maybe just do that ad hoc for now?

[cldellow]

Options for migration scripts:

• https://david.rothlis.net/declarative-schema-migration-for-sqlite/
• sqlite_utils: https://sqlite-utils.datasette.io/en/stable/

I'm not a big fan of the fact that sqlite_utils has deps on click and other things.